Two Covid variants from Britain and the US have combined into the first mutated hybrid, a scientist has warned.
The 'recombination' strain, made up partly of the highly transmissible Kent variant, raises concerns the world may be on the brink of a new phase in the pandemic.
The B117 strain, first discovered in England before the country was thrust into a third national lockdown appears to have mutated with another which has been running rampant in Los Angeles and which is resistant to antibodies.
Unlike previous mutations, a recombination can bring together multiple mutations in one go, though would still only occasionally confer more advantage of the original strains, reports New Scientist.
The hybrid was found by Bette Korber at Los Alamos National Laboratory in New Mexico, with the scientist telling other experts about it at a New York Academy of Sciences meeting on February 2.
She said she had "pretty clear" evidence of the worrying, though currently unconfirmed strain.
Dr Korber, a computational biologist, told the meeting: "This kind of event could allow the virus to have coupled a more infectious virus with a more resistant virus."
It comes after two research groups said they hadn't seen any evidence for recombinations during studies in December and January.
It remains unclear whether any hybrid could create more dangerous variants or how much of a threat the potential new discovery would pose.
SARS-Cov-2, which started the pandemic, was likely a recombination itself.
Sergei Pond, of Temple University in Pennsylvania, said: "We may be getting to the point when this is happening at appreciable rates."
The professor searches for recombinants by comparing thousands of genome sequences uploaded to databases, but remains unconvinced of widespread hybrids at present.
But he added "coronaviruses all recombine, so it’s a question of when, not if".
